1. Technical Field
The present disclosure relates to an ejector to which single-fluid atomization techniques are applied and a heat pump apparatus that uses the ejector.
2. Description of the Related Art
Atomization techniques are applied in various industrial fields, which include spray coating, spray drying, humidity control, agrochemical dispersion, and fire extinguishing, in addition to energy-related techniques, such as combustion techniques for liquid fuel. Performances desired for spray nozzles vary, depending on the application purposes of the spray nozzles. The atomization principle of a spray nozzle is variously studied, such as atomization using a turbulent flow, atomization including film thinning by widening a sprayed area, atomization using centrifugal force, or atomization using two-fluid interaction. However, a nozzle that can achieve a high flow rate, high performance in atomization, a high spray speed, a small spray angle, and flow contraction spraying at the same time through the application of the principle of single-fluid atomization has not existed.
An ejector is used for various apparatuses as a pressure reducer, which include a vacuum pump and a refrigeration cycle apparatus. As illustrated in FIG. 18, a refrigeration cycle apparatus 300 described in Japanese Patent No. 3158656 includes a compressor 102, a condenser 103, an ejector 104, a separator 105, and an evaporator 106. The ejector 104 receives refrigerant liquid from the condenser 103 as a driving flow and sucks refrigerant vapor supplied from the evaporator 106 and boosts the pressure of the refrigerant vapor before discharging the resultant refrigerant to the separator 105. The separator 105 separates the refrigerant liquid and the refrigerant vapor. The compressor 102 sucks the refrigerant vapor having the pressure that has been boosted by the ejector 104. Thus, the compression work of the compressor 102 is reduced and the coefficient of performance (COP) of the refrigeration cycle is increased.
As illustrated in FIG. 19, the ejector 104 includes a nozzle 140, a suction port 141, a mixer 142, and a pressure booster 143. Near the outlet of the nozzle 140, a plurality of communication ports 144 for communication between the inside and the outside of the nozzle 140 are provided. The refrigerant vapor is sucked into the ejector 104 from the suction port 141. Part of the sucked refrigerant vapor is guided into the inside of the nozzle 140 through the communication ports 144.
The nozzle 140 of the ejector 104 includes a diameter reduction portion near the outlet of the nozzle 140. In the diameter reduction portion, the flow velocity of the refrigerant increases and the pressure decreases. As a result, the refrigerant supplied to the nozzle 140 as the driving flow changes into a gas-liquid two-phase state from the liquid-phase state in the diameter reduction portion. That is, the ejector 104 illustrated in FIG. 19 is called a two-phase flow ejector.